Driveshaft with two-stage stiffness

A drive-train for a motor vehicle comprising:

• a power-plant configured to generate torque;
• a road wheel;
• and
• a two-stage stiffness driveshaft configured to transmit torque from power-plant to the road wheel, the driveshaft including:
• a hollow cylinder defined by a longitudinal axis, a first end, a distal second end, and having a hollow cylinder stiffness;
• and
• an inner shaft extending through the hollow cylinder along the longitudinal axis and defined by a first end, a distal second end, and having an inner shaft stiffness;
• wherein:
• the first end of the inner shaft is engaged with the first end of the hollow cylinder via a rotational clearance fit, and is configured to receive the torque from the power-plant;
• the second end of the inner shaft is rotationally fixed to the second end of the hollow cylinder such that the first end of the inner shaft will twist to a predetermined angle with respect to the second end of the inner shaft in response to the torque received from the power-plant;
• and
• the inner shaft stiffness defines a first-stage stiffness of the driveshaft and the inner shaft stiffness together with the hollow cylinder stiffness defines a second-stage stiffness of the driveshaft.